Japanese Patent Application Laid-Open No. 2008-078086 discloses a vehicle light having a light emitting diode (LED) as a light source and a light guide for controlling the light distribution pattern of light beams from the LED. FIG. 1 is a vertical cross sectional view illustrating the configuration of a conventional vehicle light. As shown, the vehicle light has a light source 100 including a light emitting device 100a facing upward. A light guide 102 is disposed above the light source 100. The light guide 102 includes a light incident surface 104, a reflecting surface 106, and a light exiting surface 108. Light beams emitted from the light source 100 can enter the light guide 102 through the light incident surface 104. The reflecting surface 106 is disposed near the rear side of a vehicle body and the entering light beams can be reflected by the reflecting surface 106 to be directed in the forward direction of the vehicle body. The reflected light beams exit through the light exiting surface 108 disposed near the front side of the vehicle body.
The vehicle light utilizing this type of light guide can project the image of the LED light source by the light guide while the image is enlarged, thereby forming a predetermined light distribution pattern. Accordingly, if the light beams emitted from the LED light source from various points of the light emitting surface have chromaticity variation (color shading), the color shading may appear in the illumination light to be projected from the light guide, thereby generating illumination light with color shading. In general, an LED light source may generate color shading, in particular, at its edge areas of the light emitting surface with ease. As a result, color shading can occur at the boundary portion of the light distribution pattern. If the illumination light has such color shading, when an object with monochromatic color is illuminated therewith, the object can be observed with different colors at different positions, thereby degrading the color rendering properties. In order to cope with this problem, it is sometimes helpful to strictly control the managing conditions of the light source with regard to color shading. However, this may hinder the mass production of light sources and also prevent cost reduction.